Refrigerating system



` E 1 631278 .June 71927 Y U. R. LORANGER ET Al.

REFRIGERATING SYSTEM Filed April 6. 1925 2 Sheets-Sheet 2 troubles may be traced, not to the Patented June 7, 1927.'

UBALD n. LonANGan im HUBERT B. LONGER, 0F DETBIL'KICHIGAN.

BEFBIGERATING BYSTEI.

' appiication ami Aprile im. semi No. 21,195. l

The invention relates' to rerigerating systems more particularly designed for domestic installations and o the type in which a suitable circulating medium such as sulphur dioxide is alternately compressed .and expanded. Apparatus of this general character is commercially obtainable and yusually comprises a compressor of the reciprocating piston type having suitable checkvalves, a

condenser for the compressed medium, an `p expansion valve and expansion coils, the latter being usually immersed in a container filled with brine.

In order to obtain a satisfactory appa ratus for domestic installations, it is necessary to have a construction which is automatically maintained in operation and requires very little attention to keep it in runnin condition forvlong periods of time. One o the chief objections to commercial machines of the present time is that the frequently require the attention of a s illed workman because of mechanical troubles which interfere with the proper operation of the machine and this constant servicing of the apparatus fis notonly a source of annoyance to the householder but is a factor contributing greatly tothe 'operating cost.

As a' result of careful study of the servicel diiculties of' machines using sulphur dioxide or the circulating medium, we have found that about ninety percent of the mechanical construction of the apparatus or to the usual wear and tear due to constant operation, but rather to certain underlying causes. not readily apparent, which in the last analysis are due to' the eiect on the materials used in the construction by an acid that is formed from the combination of moisture with the refrigerating medium. The detrimental effeet of the acid is not primaril inthe actual eating away of the metalic parts by corrosion although such results have en observed, but rather in the formation o foreign substances in the circulating medium itself which act as abrasives on the mechanical parts of theapparatus and seriously affect the working of the mechanism.

The ordinary materials of construction, artieularly the ferrous metals are chemicalliy attacked by the refrigerating medium with the formation of sulphides and other substances that are then mechanically entrained in the circulating medium and carstem. These subine abrasive parvalve seats,

ried to all parts of the s stances are in the form o l ticles and are deposited on the bearings and piston, stant abrasion of the working parts until it becomes impossible to maintain compression inv any part of the line. The entrained abrasive particles also have a blasting action on the valves, valve seats and other working arts of the mechanism. As a. result of this abrasive and blasting other troubles arise. The friction in the bearings makes the operation of the machine difficult, overloads the motor and often causes the belt to slip, to burn and to run off. The valves become improperly seated preventing the proper closing and permitting the escape of gases through the same. The* expansion valve is also affected by the corrosion and abrasive action and when it gets out of order the gases are allowed to continuously run over, raising a back pressure and causin the machine to operate continuously whic results' in improper and incomplete compression and a continuous flow through the line regardlessof the temperature of the ice box. The constant operation of the motor results in overheating the same and often serious injury. In case the ex ansion valve happens to stick while closed, t e machine will pump a vacuum and finally reaches a point where action, a great many 4resulting in the conthe belt slipsnthe motor is overloaded and p sometimes seriously damaged. Thus, as a result of the corrosion of the parts by the sulphur dioxide a great deal of damage may be done to the apparatus and it often involves return of the machine -tothe factory andre lacement of all valves, stems and seats, pistons and cylinder sleeves.

' The corrosion of the metals by the rerigerating medium is lar presence of sulphurous an sulphuric acids ely due to the formed by the presence of moisture in the* circulating line. The moisture may presf ent due to the incomplete drying or it may be introduced through condensation from the v the acid formed frpin the sulphur dioxi e, at least to such an extent as to form an abrasive substance that can be entrained by the circulating medium and deposited in the Working parts. It is, of course, also necessary that the materials chosen should be suitable for the mechanical functioning of the parts, that is, they must be of sufficient strength, wear resist-ing qualities, etc. The above mentioned object has been obtained in the construction hereinafter fully described and illustrated in the accompanying drawings wherein Figure 1 represents the refrigerating system showing the circulation of the sulphur dioxide;

Figure 2 is a section through the compressor substantially on the line 2 2 of Fgure 1;

Figure 3 is a section through the expansion valve on the line 3 3 of Figure 1;

Figure 4 is a. fragmentary section at right angles to Figure 2 showing inlet and'exhaust valves.

As illustrated in Figure 1, A is the compressor mounted upon a suitable base B and driven by theelectric motor C. The outlet connection D of the compressor is connected to the condenser coils E, the latter being supported in a suitable frame B also mounted on the base B. F is a scrubber or purifier depending from the base B and comprising a suitable container or reservoir connected to the condenser coils. G is a conduit extending from the scrubber and leading` to the brine tank H Where the refrigerator is located. The conduit is connected to an eX- pansion valve I which in turn, is connected to the expansion coils J arranged within the the brine tank. The outlet conduit L from the expansion coils leads back to the compressor A and completes the circulating system.

The mechanical features of the system as illustrated in Figure 1 form no part of this invention, but in order to set forth the novel features we will now describe the various materials which have been selected after a long series of tests as being most suitable for the parts of the refrigerating system in order to prevent the formation of abrasive substances in the refrigerating medium. The main point is to eliminate the use of ferrous alloys wherever possible, but in order to secure the best mechanical results from the compressor, 1t is not practicable to use non-ferrous alloys entirely. We have found. however, with certain types of ferrous alloys the action of the sulphur dioxide is so slight as to be commercially negligible, for after the surface has been covered with a light oxide coating further corrosion is prevented and this oxide coating is not of Such a nature as to result in theformation of an abrasive substance that can be entrained in the circulating medium. The best alloy of this type we have found to be a hig chromium steel with or without the addition of nickel. For example, an alloy which contains eight percent chromium and eleven percent nickel is well suited for certain parts where non-ferrous alloys are impractical.

In the compressor as illustrated in Figure 2. the piston M, cylinder sleeve M, crank shaft N, connecting rod N and piston pin N2 are all composed of a chromium steel alloy containing at least seven percent of chromium. The compressor casing O is cast from aluminum bronze preferably containing ninety percent copper and ten percent aluminum. The piston rings l are made of high phosphor bronze containing the minimum of zinc and tin, this material also being used for the crank shaft bearings Q, and the connecting rod bearings Q. The gravity seated inlet and outlet valves R and R are preferably made of duralumin or any other hardened aluminum alloy. This material, in addition to imparting the non-corrosive properties, also provides a light weight valve which facilitates the operation of the valves and renders the same quiet in action.

The copper tubing, however, is not satisfactory as commercially obtained because there is always a certain amount of scale and oxides within the tubing which will be attacked by the refrigerating medium with detrimental results to the system. To overcome this difficulty all of the tubing employed in the system is first treated chemically to remove all traces of scale and foreign matter. Vhile many different cleaning solutions might be used for this purpose, We have found that a mixture of seven percent Sulphuric acid, three percent nitric acid and ninety percent water is the most satisfactory all-around cleaning agent. This solution will remove all scales, both black and red and will also remove the more resistant combination of scale and lubricant which is deposited during the manufacture of the tubing by the extruding process.

The fitting S at the inlet end of the compressor is made of an aluminum bronze casting while the main control valve S contained therein is preferably formed of a chromium steel alloy ofthe type above described.

The scrubber preferably comprises a cylindrical copper container F in which is arranged a bronze filtering screen F2 containing within the same particles of zinc, the purpose being to absorb any acids in the circulating medium by the reaction with the zinc. An absorbent material such as asbestos surrounds the screen and serves to take up abrasive particles and prevent their circulation with the sulphur dioxide. The scrubber has the effect of reducing the corrosion of the sulphur dioxide upon the various parts of the /refrigerating system but does not in itself sufficiently prevent the lio corrosion to allow the use of the ordinary materials of construction in the other parts of the system.

The expansion valve I comprises a housing of aluminum bronze containing a diaphragm T of phosphor bronze sheet metal having below ten percent tin or zinc. The valve T and associated arts between the inlet U and outlet U ci) the housing are preferably madeof `phosphor bronze, while the coil spring T2 bearing against the valve is made of a nickel silver alloy containing five to eighteen percent silver. The spring T3 on the opposite side of the diaphragm from ythe spring T2 does not come' in contact with the refrigerating medium, but to prevent any possible corrosion, due to moisture or escaping sulphur dioxide it is preferably made of phosphor bronze.

From the above description it Will' readily apparent that our refrigerating sys- Q tem uses non-corrodible materials at all points in the circulating line. It is not sufficient to use non-corrodible materials for a portion only of the parts exposed to the re rigerating medium or While this would prevent the direct corrosion of such parts, it would not prevent the formation of the abrasive substances at the oints in the line where the corrodible materials are employed and therefore, would not prevent the abrasive and blasting action 'upon all of the mechanical parts of the apparatus. Therefore, it is an essential part of our invention that all of the parts of the refrigerating.

system which are exposed to the refrigerating medium should be composed of materials which are sufiicientl non-corrodible to prevent the formation o any abrasive substances.

In the foregoing specilication, we have described the preferred materials which are used inthe various parts of the refri ersting system, but we wish it understoo that our invention is not limited to the exact materials specified since it is obvious that other suitable materials that are resistant to the action of the acids formed from sulphur dioxide might be employed as substitutes.

What we claim as our invention is:

l. A refrigerating apparatus comprising a pump for compressing a refrigerating medium having acid forming properties, a condenser for the compressed medium, expansion coils forthe condensed medium, and a valve controlling the flow of the condensed medium from the condenser to said coils, certain parts of the' elements aforesaid being formed of materials substantially non-corrodible by the acid formed from said me dium.

2. A refrigerating apparatus including Amechanical means vfor compressingr a refrigerating medium such as sulphur dioxide having acid forming properties, a condenser for the compressed medium, and a circulating pipe line connected to said condenser and compressing means,of parts of said compressing means and condenser exposed to the refrigeiating medium being composed of materials substantially non-corrodible by the acid formed from the refrigerating inediuin. y

3. vA refrigerating apparatus comprising a closed circuit for a refrigerating medium such as sulphur dioxide having acid forming roperties, said circuit inc uding a mechanical compressor in which the parts exposed to the refrigerating medium are composed 'of materials substantially non-corrodible by the acid formed from said medium.

4. Iii a refrigerating apparatus employing Sulphur dioxide, the combination of a compressor, condenser and expansion chamber, all connected together to form a closed circuit in which all ofthe parts exposed to the sulphur dioxide are composed of materials substantially non-corrodible by sulphurous and sulphuric acids.

5. In a refrigerating apparatus employcal action of sulphurous and sulphuric acids to prevent the formation of abrasive impurities such as metallic sulphides that can be entrained in and circulated by said medium. i

6. In a refrigerating apparatus employing a refrigerating medium which in itself is not a corrosive but which has the property of forming a corrosive substance under commercial operating conditions, the combination of a compressor, condenser and expansion chamber connected together to form a closed circuit, the parts of the elements aforesaid which are exposed to the medium being composed of materials which are sulficiently resistant to tlie chemical action of said corrosive substance to prevent the formation of solid abrasive impurities that can be entrained in and circulated by said medium.

7. In a refrigerating apparatus employing sulphur dioxide, the combination of a compressor, condenser and expansion chamcuit, said compressor having a plurality of movable parts and valves in said circuit for maintaining the sulphur dioxide under iis ber connected together to form a, closed cir- Y which are exposed to the sulphur dioxide also having the chemical property otl being substantially non-corrodible hy sulphur-ous und sulphur-ic acids.

8. In a refrigerating apparatus employing sulphur dioxide, the combination of u compressor, condenser und expansion chiunber connected together to 'forni u closed circuit in which all of the parts exposed to the sulphur dioxide :1re composed ot' nuiterizils substantiallyl non-corrodihle by sulphurous and sulphuric acids` certain of :said purts requiring' great strength beine' of steel having` at lenst Tf/ chromium and the other of said parts being of non-ferrous alloys.

9. In a refrigeratin;r apparatus employing sulphur dioxide, the comhinution ol' n compressor, condenser und expansion chumber connected tog-ether to form n closed circuit, the elements uforesuid including vulves, cylinders, pistons, pitmen, cranks. beurings. springs nndcouduits :ill exposed to the sulphur dioxide, all of suid exposed parts heiner composed of niuteriuls which are substiintinlly non-corrodihle by sulphurons and sulphuric acids.

In testimony whereof we uix our signzu tures.

UBALD R. LORANGER. HUBERT R. LORANGER. 

